Technical Field
The present invention pertains generally to the field of deposition of thin films, more particularly, to deposition of films without the use of a vacuum chamber.
Background
Pulsed laser deposition (PLD) of thin films has a number of advantages over other methods such as the accurate control of film thickness, uniform coating, good control of the film composition, and the capability of selective deposition in specified regions. The technologies of the PLD are normally applied in the vacuum to avoid the interferences and obstruction of the ambient gases on the particles ablated from the target. However, PLD in the vacuum is expensive and is limited to the substrates of small size that can fit in the vacuum chamber.
Implementing PLD in ambient air or at atmospheric pressure may include the following characteristics:    1) At atmospheric pressure the mean free path of the ions of the target material knocked out by a high-energy laser beam from a target does not exceed one or two millimeters. This is due to very many collisions of the plume plasma ions with the molecules of the gases in ambient air.    2) PLD in ambient air has and a risk of chemical reaction of the plume ions with atmospheric oxygen leading to oxidation and other highly undesirable chemical transformations of the target material being deposited on the substrate.